1. Field of Invention
The present invention is generally related to packaging containers, for holding materials or goods, and more particularly, to such containers having a degassing valve.
2. Background
As products are packaged and sealed, air may become entrapped inside the package or gases may be produced by the products. For example, many dry and frozen foods (e.g., coffee, tea, snacks, flour, sugar, pasta, pet food, etc.) are packaged while hot. The hot or warm contents or materials cause (while the contents cool) pressure to build in the interior of the packages. To prevent excessive pressure from building up, some packages are degassed through valves provided on the package. Generally, the use of degassing valves in the top or in the sidewall of a package or container for the release of entrapped air or gases is known in the art. One advantage of degassing is that it helps preserve the products within the package.
The prior art discloses several methods for degassing. The use of a pressure release valve covering a hole in the wall of a container is known in the art. Also known are hermetic packages having a valve mounted on a wall panel with filters for venting gases within. Degassing valves that include a manually moveable element for enabling the venting of gas from the interior are also known. Examples of various prior art containers of the types discussed above are shown in U.S. Pat. Nos. 5,782,266; 5,893,461; 5,992,635; 6,056,439; and 6,070,728.
Degassing valves are typically used on packages such as bags, gusseted packages, and rigid plastic and metal containers, such as cans. Degassing valves are often engineered to also restrict the entrance of outside air. Ambient atmosphere contains degrading oxygen and deleterious microbes that are preferably prevented from entering the package. Several methods have been developed for preventing contact of atmospheric air with the contents of a package or container. One known method of preventing outside air from entering a package is the use of a sealed, rolled end on containers such as cans. Typically, a container's top or bottom is rolled or curled with the body or sidewall. A current methodology includes the insertion of a sealant or lining compound contained within a rolled end seam. The sealant is rolled into the seam; specifically, as the can body wall and end wall are rolled together to form a double seam, the compound is disbursed circumferentially (i.e., curled) within the rolled end, thus forming a continuous gasket that prevents the entrance or escape of air into the interior of the container.
The solutions provided by the prior art for allowing gases to escape from the package interior (and preventing the ingress of air) are expensive to fabricate and difficult to insert into the packaging. The present invention overcomes these issues.